SNAP PID MODULE REFERENCE
SNAP PID Module User’s Guide
25
Binary/Hexadecimal Conversion Chart
For using PID module control words and reading status flags, use the following chart to convert
binary data to and from hexadecimal (or “hex”) values:
1
Setpoint Hi
1 = Setpoint input is above the Setpoint Hi limit and is clamped to that value for calculating PID
output. In Auto Mode, this flag is checked when PID output is calculated. If setpoint input re-enters
the normal range, the flag will clear at the next scan time.
2
Process Lo
1 = Process input is below the Process Lo limit and is not suitable for calculating PID output. In Auto
Mode, this flag is checked when PID output is calculated. When this flag is set, the Process Quality
flag is also set and the module is forced to Manual mode. The output will not change. After the
condition is fixed, you must change back to Auto Mode. The flag will clear when the PID output is
calculated.
3
Process Hi
1 = Process input is above the Process Hi limit and is not suitable for calculating PID output. In Auto
Mode, this flag is checked when PID output is calculated. When this flag is set, the Process Quality
flag is also set and the module is forced to Manual mode. The output will not change. After the
condition is fixed, you must change back to Auto Mode. The flag will clear when the PID output is
calculated.
4
Output Lo
1 = Output is clamped to the Output Lo clamp value. In Auto Mode, this flag is checked when PID
output is calculated. This flag is for indication only and will clear when the output is above the clamp
value.
5
Output Hi
1 = Output is clamped to the Output Hi clamp value. In Auto Mode, this flag is checked when PID
output is calculated. This flag is for indication only and will clear when the output is below the clamp
value.
6
TPO Status
1 = TPO is in the “On” portion of the TPO period.
0 = TPO is in the “Off” portion of the TPO period.
7
Process Quality
1 = Process input was not suitable for the PID calculation as it was calculated using the Hi/Lo
process limits. In Auto Mode, this flag is checked when PID output is calculated. If the flag is set, the
mode is forced to Manual. After the condition is fixed, you must change back to Auto Mode. The flag
will clear when the PID output is calculated.
If this flag is set after an initial powerup or reset command, the PID module failed to load variables
from its flash memory, and all configuration parameters and variables are at factory default settings.
Binary Data
Corresponding
Hex Value
Binary Data
Corresponding
Hex Value
0000
0
1000
8
0001
1
1001
9
0010
2
1010
A
0011
3
1011
B
Bit
Flag Name and Description
