Use the WREG function in Ladder Logic:
LD IR33 // Load Temperature
GT K70 // Greater than 70c?
OUT OR40 // Trigger pre-alarm relay
The standard manual would flag IR33 as an "Invalid Address." Ignore that error. The compiler accepts it if you disable "Strict Address Checking" in the system flags (Flag 101).
If your temperature is oscillating (swinging up and down wildly) or taking too long to stabilize, use Auto-Tune. s661 controller manual exclusive
The S661 is a micro-processor based temperature controller designed for precision control. It typically features a dual 4-digit LED display, PID auto-tuning, and multiple output options (Relay, SSR, or 4-20mA).
Key Applications:
The standard S661 manual teaches you the basic operations: LD, AND, OR, OUT.
A common complaint in the official manual's FAQ is: "Inputs sometimes stay high when switch is open." Use the WREG function in Ladder Logic: LD
The official fix is to buy shielded cable. The exclusive fix is a hardware mod.
The official manual provides a table for Input Registers (IR1 to IR32) and Output Registers (OR1 to OR16). That is the "public" map. The standard manual would flag IR33 as an "Invalid Address
The standard manual walks you through the ladder logic programming via the RS-232 port using the V3.2 software. However, the S661 Controller Manual Exclusive reveals the existence of X-Mode, an emergency shell interface.
