Two versions of operator interface are used with the M4500 Controller:
The D4591 Display/Keypad incorporates a 2-line X 40-character back-lit LCD display with a 3-row X 8-column sealed keypad. Back-lit LCD technology at 0.19" character height provides both high visibility in low light conditions and high character density. The keys on the keypad are spaced at 0.75" spacing.
The display interfaces with the M4500 via a 26 pin ribbon cable. Communication is parallel at TTL levels and must be mounted in close proximity with a maximum cable length of 8 feet.
The D4591 is equipped with a gasket and is fully sealed to NEMA 12 levels to prevent the ingress of contaminates.
The D4591 can be used as a general purpose interface. Complete control of the display is provided through commands accessed through the user program of the PLC section.
Commands such as: "position cursor", "clear display", "enter characters into display", "blink character", as well as an ASCII string conversion system function allow easy and complete control of the display directly in the M4500 user's program.
The PLS program commands are resident in the firmware of the M4500 and can either be enabled or disabled in the user's program. When enabled, the display performs as a programming terminal for the PLS section.
The keypad of the D4591 is a 3-row X 8-column sealed keypad which can either be used as a general purpose operator interface or to implement the PLS programming commands. Key depressed decode is performed automatically by the M4500 with the key number depressed mapped directly to an internal memory location.
The keypad overlay itself simply contains clear windows over the keys. Customization of the keypad is performed by placing a placard behind the overlay (between overlay and keys) with the desired key legends. This allows complete customization of the keypad in quantities as low as one.
The HMI operator interface utilizes a Maple Systems high-performance 7.0" TFT LCD touchscreen display. It includes 2-serial ports (RS-232 & RS-485, COM1, COM2 & COM3), 2-LAN ports (10/100 base-T RJ-45) and 1-USB 2.0 port.
The display has a maximum resolution of 800 x 480 with an input voltage of +24VDC, power consumption of 19.7 W (820mA @ 24VDC), environmental rating of NEMA4 with an IP66 compliant front panel.
The HMI connects to the M4500 via the 9-pin RS-232 PROG port. The maximum length for an RS-232 connection is 50 feet. If a longer cable length is needed then an RS-232 to RS-485 converter can be used to extend the range.
Cable length to the M4500 is no longer an issue. The maximum permissible length between a RS-485 driver and receiver is 4000ft. The serial ports of the Maple Systems HMI can be configured as either RS-232 or RS-485. With the serial port configured as RS-485 and using the converter then the HMI can be mounted a long distance away from the M4500.
The HMI runs an application program to interface and communicate with the M4500. Programs have been developed for the various system upgrades. All of the functions and features of the D4591 Display/Keypad are included in the application program.
A key feature of the HMI is the ability to upload and store (or download and restore) the PLC program, setup parameters and timing channel setpoints. Everything to completely restore the M4500 to the previous state can be done with the HMI in only a couple of minutes. No laptop, software or cable needed.
