Are there any operating problems with the 120 V ac and 230 V ac versions?
Due to the low current consumption of the PLC-RELAY, the PLC-RELAY could remain energized even when switched OFF. The problem is associated with the use of Digital Output PLC cards that have a TRIAC output, and occurs because the OFF State of the TRIAC is between 2mA to 8mA. To work around this problem the suggested practice is to use digital output cards with a 24 V dc voltage level. This not only reduces the current consumption, but also increases the density of the PLC. This practice also reduces PLC Rack size, and is more economical. If the products are already installed and wired, the addition of a bleed-off circuit is the only remaining solution. In order to calculate the correct componentry, it is suggested that the current flowing in the OFF State be measured. While the easiest component would be a resistor connected in parallel to the input terminations, the solution requires the use of a high wattage resistor that adds an additional heat source in the control system. Phoenix
