simplify status/count update logic

README.md

@@ -54,3 +54,17 @@ runScript "$(counterbox_DIR)counterbox_v2.cmd" "NAME=COUNTERBOX, ASYN_PORT=CBOXV
 | \$(PREFIX):\$(NAME):ELAPSED-TIME      | Time Counterbox has been measuring for                               |
 | \$(PREFIX):\$(NAME):M_                | Current count on channel. (1-10 depending on box)                    |
 | \$(PREFIX):\$(NAME):CHANNELS          | Number of available channels (4, 8 or 10)                            |
+
+## Testing
+
+The 2nd generation systems have two test channels that can be used to output
+signals at a variable rate. These can be used to ensure the other channels are
+working and to check the IOC - Nicos integration. These can be loaded at
+runtime via the following
+
+```
+epicsEnvSet("LOAD_TEST_PVS","")
+runScript "$(counterbox_DIR)counterbox_v2.cmd" "NAME=COUNTERBOX, ASYN_PORT=CBOXV2, CNTBOX_HOST=TestInst-DAQ1:2000"
+```
+
+See the file [counterbox\_v2\_test.db](./db/counterbox_v2_test.db)