Sigma - Communications with the controllers is very slow.

Issue

Communications with the controllers is very slow.

Product Line

Satchwell Sigma

Environment

Slow communications

Displaying objects seem to lock up

Globals

V53 hardware

Cause

Communications with the controllers is very slow. Objects will display correctly once, but if the display is carried out several times, or if an object is overridden, the server appears to lockup.

Resolution

The issue was caused by two Sigma objects being globally transmitted at the rate of 12 per second. The two objects were Programmable and the programme had been incorrectly written as follows;

10 IF POINT 0|108 = 0.000000 THEN RETURN "Ch1  Off"
20 IF POINT 0|108 = 1.00000 THEN RETURN "Ch1 Start"
30 IF POINT 0|108 = 2.00000 THEN RETURN "Ch1 Running"
40 IF POINT 0|108 = 3.00000 THEN RETURN "Ch1 Shutdown"
50 IF POINT 0|108 = 4.00000 THEN RETURN "Ch1 Service"

The above object is incorrect because it does not specify True or False.

Because globals are transmitted on "change of state" the global was being transmitted with every scan of the object file.

It is recommended that the object is changed as follows.

10 IF POINT 0|108 = 0.000000 THEN RETURN FALSE "Ch1  Off"
20 IF POINT 0|108 = 1.00000 THEN RETURN TRUE "Ch1 Start"
30 IF POINT 0|108 = 2.00000 THEN RETURN TRUE "Ch1 Running"
40 IF POINT 0|108 = 3.00000 THEN RETURN TRUE "Ch1 Shutdown"
50 IF POINT 0|108 = 4.00000 THEN RETURN TRUE "Ch1 Service"