diff --git a/F1:F103/shutter/Readme.md b/F1:F103/shutter/Readme.md
index 999afd0..3519dc4 100644
--- a/F1:F103/shutter/Readme.md
+++ b/F1:F103/shutter/Readme.md
@@ -4,6 +4,21 @@ Shutter control
 Works with bi-stable shutter. 
 You can find the device in `/dev/shutterX` (symlink to `/dev/ttyUSBX`).
 
+After powered on, the device will try to close shutter (during one second). 
+
+The CCD (or manual) controlled input allows to open/close shutter by changing its level (depending on `ccdactive` parameter). 
+If current configuration can't open or close the shutter immediately, it will be opened/closed as soon as possible, while the input holds its level.
+
+When the shutter is closed, the device will send over USB a message like
+```
+exptime=10000
+shutter=closed
+```
+with calculated value of opened time and current shutter state. 
+If the error occured and shutter can't be closed, user will read `exp=cantclose`, shutter will come into error state. You should close the shutter by external command in that case.
+
+After the shutter completely opened, user can read a message `shutter=opened`.
+
 ## Pinout
 
 **PB0** (pullup in) - hall (or reed switch) sensor input (active low) - opened shutter detector
@@ -58,20 +73,20 @@ You can find the device in `/dev/shutterX` (symlink to `/dev/ttyUSBX`).
 * 'v' - get Vdd (/100V)
 * 'V' - get shutter voltage (/100V)
 
-
-If you will enter wrong long message, will receive its echo back. Any wrong short command will show help list.
+Any wrong long message will echo back. Any wrong short command will show help list.
 
 ## Shutter control
-Commands '0', '1' and '2' should be used only for debugging purposes.
+Commands '0' ...  '3' should be used only for debugging purposes.
 To open/close shutter use only 'O', 'C' and 'E' commands.
 
 When opening or closing shutter you will first receive an answer: `OK` if command could be done or `ERR` if there's insufficient voltage on capacitor or shutter is absent.
 After opened the message `shutter=opened` will appear. After closing you will receive messages `exptime=xxx` (when `xxx` is approx. exp. time in milliseconds) and `shutter=closed`.
 
 Command 'E' could return `OK`, `ERR` or `ERRNUM`/`I32OVERFLOW` in wrong number format (number could be decimal, 0x.. - hexadecimal, b.. - binary or 0.. - octal).
+"Status" command in this case will return `shutter=exposing` and `expfor=xxx` - the given exposition time.
 
 When exposition starts you will receive message `OK` and `shutter=opened`. After its end you'll got `exptime=...`, `shutter=closed`.
-If shutter can't be closed, you will give a lots of "exp=cantclose" and different error messages until problem be solved. To stop this error messages give command 'O'.
+If shutter can't be closed, you will give a lots of `exp=cantclose` and different error messages until problem be solved. To stop this error messages give command 'O'.
 
 ## Different commands
 * 'A' will show raw values for all ADC channels: 0. - capacitor voltage, 1 - MCU temperature, 2 - MCU Vdd. You will give messages like `adcX=val`.
@@ -82,7 +97,7 @@ If shutter can't be closed, you will give a lots of "exp=cantclose" and differen
 
 * 'v' - `vdd=val`, val in V*100
 
-* 'V' - "voltage=val", val in V*100
+* 'V' - `voltage=val`, val in V*100
 
 * 'S' - several answers:
   * `shutter=`: `closed`, `opened`, `error`, `process`, `wait` or `exposing` - shutter state 
@@ -104,9 +119,17 @@ workvoltage=700
 shuttertime=20
 waitingtime=30
 shtrvmul=143
-shtrdiv=25
+shtrvdiv=25
 ```
 
-* ``
-* `ccdactive` - is level of 'CCD' input to open shutter (1 to open on high and 0 to open on low signal)
-* `hallactive`
\ No newline at end of file
+* `userconf_sz` - "magick" number to determine first non-empty record in flash storage. The aligned size of one record in bytes.
+* `ccdactive` - is level of 'CCD' input to open shutter (1 to open on high and 0 to open on low signal), change this value with command `c`.
+* `hallactive` - the same for Hall sensor or reed switch mounted on shutter to indicate opened state, change with `h`.
+* `minvoltage` - voltage level on discharged capacitor (V*100 Volts), when shutter is in opened/closed state, the power will be off from coils reaching this level. Can be from 1V to 10V. Change with `<`.
+* `workvoltage` - minimal level (V*100 Volts) of charged capacitor to start process of opening/closing, you can open/close shutter only with higher voltage. Can be from 5V to 100V. Change with `>`.
+* `shuttertime` - maximal time (milliseconds) of holding active voltage on shutter's coils. Can be from 5ms to 1s. Change with `#`.
+* `waitingtime` - waiting time for the shutter to finish its job. The expose time can't be less than this value. Can be from 5ms to 1s. Change with `$`.
+* `shtrvmul` - multiplier to calculate capacitor voltage from voltage on ADC input of MCU. Vcap = V*shtrvmul/shtrvdiv. Can be from 1 to 65535. Change with `*`.
+* `shtrvdiv` - divider of capacitor voltage calculation. Can be from 1 to 65535. Change with `/`.
+
+All changes of configuration processed in RAM and acts immediately after changed. If you want to store changes, use command `s`.
\ No newline at end of file
diff --git a/F1:F103/shutter/flash.c b/F1:F103/shutter/flash.c
index f400eb2..d67241c 100644
--- a/F1:F103/shutter/flash.c
+++ b/F1:F103/shutter/flash.c
@@ -187,6 +187,6 @@ void dump_userconf(){
     USB_sendstr("\nshuttertime="); USB_sendstr(u2str(the_conf.shutterrime));
     USB_sendstr("\nwaitingtime="); USB_sendstr(u2str(the_conf.waitingtime));
     USB_sendstr("\nshtrvmul="); USB_sendstr(u2str(the_conf.shtrVmul));
-    USB_sendstr("\nshtrdiv="); USB_sendstr(u2str(the_conf.shtrVdiv));
+    USB_sendstr("\nshtrvdiv="); USB_sendstr(u2str(the_conf.shtrVdiv));
     newline();
 }
diff --git a/F1:F103/shutter/main.c b/F1:F103/shutter/main.c
index 4da817c..523a1fa 100644
--- a/F1:F103/shutter/main.c
+++ b/F1:F103/shutter/main.c
@@ -41,7 +41,7 @@ int main(void){
     hw_setup();
     USB_setup();
     // close shutter and only after that turn on USB pullup
-    while(!close_shutter() && Tms < the_conf.waitingtime) IWDG->KR = IWDG_REFRESH;
+    while(!close_shutter() && Tms < 1000) IWDG->KR = IWDG_REFRESH;
     USBPU_ON();
 
     uint32_t Terr = Tms + 2*ERRPERIOD;
diff --git a/F1:F103/shutter/shutter.bin b/F1:F103/shutter/shutter.bin
index 31e0f25..82e4095 100755
Binary files a/F1:F103/shutter/shutter.bin and b/F1:F103/shutter/shutter.bin differ
diff --git a/F1:F103/shutter/shutter.c b/F1:F103/shutter/shutter.c
index 6419177..afe2b8b 100644
--- a/F1:F103/shutter/shutter.c
+++ b/F1:F103/shutter/shutter.c
@@ -39,7 +39,7 @@ static const char *regstates[4] = {
 
 static const char *opcl[2] = {"closed", "opened"};
 
-shutter_state shutterstate = SHUTTER_ERROR;
+shutter_state shutterstate = SHUTTER_RELAX;
 static shutter_state nextstate = SHUTTER_RELAX;
 
 static uint32_t Tstart = 0, Texp = 0, Topened = 0;
@@ -117,7 +117,7 @@ void process_shutter(){
             }
         break;
         case SHUTTER_WAIT: // wait for mechanical work done
-            if(Tms - Tstart > the_conf.waitingtime){
+            if(Tms - Tstart >= the_conf.waitingtime){
                 SHTRHIZ();
                 shutterstate = nextstate;
                 int h = CHKHALL();
diff --git a/F1:F103/shutter/version.inc b/F1:F103/shutter/version.inc
index 9e69f18..bf5098f 100644
--- a/F1:F103/shutter/version.inc
+++ b/F1:F103/shutter/version.inc
@@ -1,2 +1,2 @@
-#define BUILD_NUMBER "103"
-#define BUILD_DATE "2023-12-07"
+#define BUILD_NUMBER "107"
+#define BUILD_DATE "2023-12-08"