Implement a 4 channel, 2 wire 4-20ma transmitter

I am looking for a skilled freelancer to help implement a board level 4 channel, 2 wire 4-20ma transmitter for my project. The requirements for this project are as follows: Measurement Range: - The transmitter should have a measurement range of 4-20ma. Accuracy: - The desired accuracy of the transmitter should be around 1-3%. Hardware Environment: - The transmitter should be able to withstand harsh outdoor conditions. Ideal Skills and Experience: - Experience in designing and implementing 4 channel, 2 wire 4-20ma transmitters. - Knowledge of industrial settings and the ability to design for harsh outdoor conditions. - Attention to detail to achieve the desired accuracy of 1%. I would prefer to implement this with an I2C signal from my PIC32 - but I am open to other suggestions (Note the project is a bit short of pins so using a pwm signal x 4 is not great - unless I add another small uC to interface between the PIC32 and the current transmitter. I am looking at the Max2900 part - but this needs ? 4 x PWM signals for control. The purpose of this project is to add 4-20ma loop control primarily of VSDs (Variable speed drives / valves in an agricultural environment) If you have the necessary skills and experience, and can meet the requirements for this project, please submit your proposal.